Just spent 6 hours chasing a faulty temperature reading on the 737

A gauge kept showing a hot start. Pulled the thermocouple, tested it. Fine. Checked all the wiring. Clean. Even swapped the ECU. Nothing. Turned out it was a loose ground wire behind the panel. Hidden under a zip tie. 6 hours for a 5 minute fix. Anybody else had a simple ground wire eat up a whole shift?

2 comments

2 Comments

kim_hart71d agoMost Upvoted

And I bet you stood there staring at that zip tie for a solid minute after you found it, just feeling dumb. I did the same thing once on a King Air. Spent like 4 hours swapping out alternators and regulators, cussing up a storm, only to find a ground wire that looked like it was chewed on by a squirrel. It was bare copper touching the firewall and causing all sorts of voltage spikes. Now my first move on any weird electrical issue is to just wiggle every ground strap I can find. My coworkers think I'm crazy but at least I'm not the guy wasting a whole shift on a loose screw anymore.

brooke4751d ago

Yeah, that "hidden under a zip tie" part got me. I used to be one of those guys who'd blame the expensive parts first, like the ECU or the thermocouple. Thought grounds were too simple to cause that much trouble. But after chasing a ghost in a Cessna 172 for almost a whole day only to find a corroded ground lug under the fabric tape, I learned my lesson. Now I always check the basics first, even if it feels like a waste of time. A bad ground can mess with everything and hide really well.